Cutting machine with knife sharpener



y 10, 5 T. T. CARAPUCCI 2,753,670

CUTTING MACHINE WITH KNIFE SHARPENER Filed Oct. 15, 1954 Racy 1' Oarapucci -er: 0.41:. 6 Aaezg CUTTING MACHINE WITH KNIFE SHARPENER Tracy T. Carapucci, Aldan, Pa., assiguor to Eastman Machine Company, Bnfialo, N. Y.

Application October 13, 1954, Serial No. 462,604

1 Claim. (Cl. 51-246) This invention relates to a power-actuated. cutting machine for textiles having an upright, vertically reciprocating knife adapted to cut a plurality of layers of cloth in the manufacture of wearing apparel. More particularly, it relates to a cutting machine of the above type having a self-sharpening mechanism provided thereon for maintaining the knife in properly sharpened condition, and has for an object to provide an improved sharpening mechanism therefor.

In cutting machines of the above type, the condition of the knife edge is a very important factor, since efliciency of operation determines the amount of time consumed and the quality of production work produced. Hence, precision knives of high quality steel are essential in a machine of this type. Also, a keen, well-centered and perfectly true edge is highly desired, in, fact essential, to provide accurate cutting and reduce unnecessary lost time due to constant fussing with the knife-edge and belabored manipulations by the operator.

Applicant has found that with prior art sharpening mechanisms, it is d'ifiicult and often impossible to repeatedly resharpen the knife edge and maintain the perfectly true edge the knife had originally when new. Due to inherent looseness in the carriage supporting the sharpening mechanism and to mis-alignmcnt of the shoes which position the abrasive-coated bands against the knife-edges, undesirable :wavy and off-center knife-edges are produced.

Applicant has also found that although flat V-shaped knife-edges are most effective in cutting some textiles, hollow-ground edges are most effective in cutting other textiles.

In view of the above, it is another object of the invention to provide an arrangement permitting the sharpening mechanism to move vertically along a path parallel to the knife edge, but restraining the mechanism against all other movement relative to the knife edge.

A further object is to provide an improved arrangement for adjusting the shoes relative to knife edge, in order that the edge imparted to the knife may be centered and true.

A more specific object is to provide a movable shoe which may be positioned in a manner to impart either a flat V-shaped edge or a hollow-ground edge to the knife, as desired.

These and other objects are effected by the invention as will be apparent from the following description taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a perspective view of'a cutting machine having the invention incorporated therein;

Fig. 2 is a view taken substantially on line 11-11 of Fig. l and showing the carriage assembly in plan;

Fig. 3 is a fragmentary view taken on line III-III of Fig. 2;

Fig. 4 is a diagrammatic view showing the shoes adjusted in one position; and

Fig. 5 is a diagrammatic view similar to Fig. 4, but showing the shoes adjusted in another position.

ted States Fatent ice Referring to the drawings in detail, there is shown a cutting machine generally designated 10, having a base 12 adapted to rest upon and be moved about a table or other surface supporting the cloth or other material to be cut. A standard 13, rigidly attached to the base 12 and extending upwardly therefrom, has supported thereon a stationary housing 14 which encloses an electric motor at. 1-5, controlled by a switch 15a, for driving a vertical knife 16. The knife 16 is reciprocated in a vertical groove 17 provided in the standard 13 by the motor through driving mechanism (not shown, since it forms no part of the invention) .to which the knife is secured at its upper end.

A bifurcated presser foot 18 is attached to the lower end of a vertically adjustable rod 19 which extends through guides 1% and 1912 provided, respectively, in the housing 14 and a movable carriage 20 to besubsequently described in detail. As well understood in the art, the presser foot 18 is adjustable to different elevations suited to different lays of material to be cut.

The movable carriage 2b is generally V-shaped and, as best shown in Fig. 2, is provided with a pair of diverging arms 21, 21 connected to a central portion 22. The carriage 20 carries dual grinding mechanism 23, 23 for mechanically grinding both faces 16a of the knife 16 to a sharp edge at the will of the operator.

Since each of the halves of the dual grinding mechanism 23, 23 is substantially identical to the other, only one half will be described. An endless band 24 of abrasive-coated material is disposed below the carriage arm 21 and is rotatably supported thereon by a pair of sheaves 25, 26. The sheave 2'5 is connected to a vertical drive shaft 27 oper-atively connected to the motor 15 within the housing '14 in any desirable manner, by means not shown, and controlled by a lever 28.

A pressure shoe 29, pivotally supported in the carriage arm 21, is provided with a pressure pad 30 which is disposed behind the abrasive-coated band 24 in the region adjacent the face 16a of the knife 16 and biamd against the band by a wire spring 31. Thus, the band is brought to bear against the face 16a of the knife.

The carriage 2%? is driven in a vertical direction by a drive shaft 32 provided with double helical gro0ves.- The drive shaft 32 is operatively connected to the motor 15 within the housing 14 in any desirable manner, by means not shown, and, is also controlled by the lever 28.

As thus far described, the cutting machine is substantially conventional and operates in the following manner:

Assuming the motor 15 to be connected to a conventional electric power supply (not shown), the motor may be energized by movement of the switch 15a to the On position, whereupon the knife 16 is rapidly reciprocated and may be applied to the lay of cloth and the presser foot 18 adjusted to the height of the lay of cloth, in a manner well understood in the art. As the cloth is cut,

the knife edge formed by faces 16a eventually becomes dull and must be sharpened. To sharpen the knife, the lever 28 is depressed, whereupon \the drive shaft 32 is rotated to actuate the carriage slowly downward for the length of the knife and then back to its extreme upper position. Concurrently therewith, the drive shafts 27, 27 are rotated in unison, whereupon the abrasive-coated bands 24, 24 are moved past the faces 16a, 16a of the knife in the direction of the arrows to restore the keen edge thereto. The pressure and position of both shoe pads 30 determine the quality of the sharpened edge.

In accordance with the invention, the carriage 20 is slidably connected to the standard 13 by a U-shaped centering member 35, preferably made in two parts bolted together at assembly, and having a cylindrical end portion 36. The centering member 35 has a pair of arms 37, 37 embracing the standard 13 and provided with spherical depressions 38, 38 disposed in alignment with a pair of vertical grooves 39, 39 formed in the standard. The centering member is snugly keyed to the standard by a pair of rollable balls 4t), 40 received in the depressions 38, 38 and disposed in engagement with the grooves 39, 39.

A V-shaped member 41 having a main tubular body portion 42 and a pair of diverging arms 43, 43 extending therefrom serves to integrate the carriage 28 to the centering member 35 as follows. The arms 4-3, 43 are locked to the carriage arms 21, 21 by screws 44, 44 after the body portion 42 is positioned on end portion 36 of the centering member and locked in proper position thereon by a set screw 45.

With the above described arrangement, the carriage 20 and consequently the dual sharpening mechanism 23, 23 carried thereby is constrained to accurate vertical movement, but is restrained against wobbly or other erratic movement relative to the knife faces 16a, 16a. Since the sharpening mechanism moves in a straight line along a single path for repeated sharpening operations, the knife edge is maintained in substantially straight edge condition throughout its useful life.

As best shown in Figs. 2 and 3, the pressure shoe 29 is provided at one end with the pressure pad 30 and has a flat bearing surface portion 47 at the other end disposed normal to the pad 38 and provided with a circular aperture 48. A shouldered pivot screw 49, extending vertically through an elongated slot 50 provided in the carriage arm 21 and through the aperture 48, pivotally supports the pressure shoe 29 for accurate movement about a vertical axis. The pivot screw may be locked to the carriage arm by a lock-nut 51 and is provided with an enlarged shank portion 52 and areduced shoulder portion 53 for snugly supporting the shoe without binding.

A thumb screw 54 is threadedly received in the carriage arm 21 in registry with one end of the elongated slot 50 and a compression spring 55 is disposed in the slot 50 in a position to bias the pivot screw 49 against the thumb screw.

The lock nut 51 is preferably, though not essentially, provided with an index member 56, rigidly attached thereto for joint movement therewith, and extending into proximity with a series of graduations 57a and 57b disposed on opposite sides of a central graduation 57, Fig. 2.

The pad 39 of the pressure shoe, as best shown in Figs. 2, 4 and is of a composite contour, having a fiat surface portion 38a and an arcuate surface portion 30b, such surfaces being adapted to individually bear against the abrasive band 24 in accordance with the position of the pivot screw 49 as will shortly be described.

The schematic view in Fig. 4 represents the setting of the shoes 29 when it is desired to impart a fiat or V-shaped edge to the knife 16. This view illustrates more clearly the conditions present when the shoes are adjusted to the positions shown in Fig. 2. The pivot screws 49 are in the outer end portions of the elongated slots 50, so that they are at the maximum distance from each other and the angle cc formed by each shoe with the centerline KK of the knife 16 is at a maximum value. This position of the pivot screws is indicated to the operator by the corresponding position of the index member 56 which is in registry with one of the graduations 57a.

When it is desired to impart a hollow-ground edge to .4 54 is turned sufficiently to move the pivot screw to the desired position, which position will be attained when the index member traverses the central graduation 5'7 and comes into registry with one of the graduations 57 b. Concurrently therewith, as shown in Fig. 5, the shoe 29 is further inclined to form a smaller angle 0 with the knife center line K-K and is also translated with respect to the knife face 16a, respectively. In this position, the arcuate portion 30b of the shoe bears against the abrasive band 24 adjacent the knife 16a. By similar adjustment of the other shoe 29 and subsequent locking of the locknuts 51 a true and well-centered hollow-ground knife edge is imparted to the knife, even after repeated sharpening operations when required, as previously explained.

Although the thumb screws 54 are preferable from an ease of adjustment viewpoint, set screws of the well known headless type may be provided instead if it is desired to minimize tampering with the adjustments by other than qualified or otherwise authorized personnel.

It will now be seen that the invention provides an improved sharpening arrangement for a cutting machine which is simple and inexpensive to manufacture, is composed of few additional parts and is easily adjustable for optimum performance.

It will also be seen that the invention is of such a nature that it can be applied to existing machines in the field of the type illustrated, thereby improving their performance.

It will also be seen that the invention will also effect savings in consumption of blades, since with more accurate cutting edges imparted to the knife on each sharpening operation, the inclination of the operator to repeatedly sharpen the knife to attain the perfection desired the knife, that is, a concave surface to the faces 16a of the knife, the lock nut 51 is loosened with a suitable wrench, whereupon the thumb-screw 54 may be screwed in a direction toward the pivot screw 49, movingthe latter against the bias of the spring 47. The thumb screw but unattainable in prior art machines is eliminated.

While the invention has been shown in one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

In a cutting machine comprising a substantially vertical standard, a vertically reciprocating knife slidably supported in said standard and having a substantially vertical double-faced cutting edge, means for sharpening said knife including a pair of abrasive coated bands movable relatively to said knife, a vertically movable carriage supporting said bands, means provided on said carriage for guiding the latter along said standard in a direction substantiallyparallel to said knife edge, a pair of movable shoes, each of said shoes having a pressure pad for maintaining a portion of said bands against each face of said cutting edge, means for individually biasing said shoes toward each other adjacent said knife edge, means including a pivot for pivotally connecting each of said shoes to said carriage, each of said pressure pads having a planar surface portion and an arcuate surface portion, means for individually positioning each of said shoes relative to said cutting edge, said positioning means including an adjusting screw arranged to coact with said pivot and to move the same, whereby said planar surface portion of the pad and said arcuate surface portion of the pad are selectively brought to bear against said band adjacent said knife edges and a V-shaped edge or a hollow ground edge, respectively, are imparted to said knife.

References Cited in the file of this patent UNITED STATES PATENTS 1,928,462 Price Sept. 26, 1933 2,183,786 Clark Dec. 19, 1939 2,183,788 Clark et al. Dec. 19, 1939 2,281,023 Clark et al. Apr. 28, 1942 2,604,741 Clark July 29, 1952 2,693,669 Riedesel Nov. 9, 1954 

